A Bayer mask is typically used to allow color component signals to be derived from any array of CCD or other sensing elements, which do not in themselves discriminate color. A Bayer mask will typically be used to derive red (R), green (G) and blue (B) signals and comprises a rectangular array of R, G and B filters. Since the human eye is more sensitive to brightness than color, and since the green signal contributes most to the perception of brightness, G filters predominate in the Bayer mask and are quincunxially sampled.
A Bayer mask decoder is used to convert a Bayer mask signal (which has for each sensing element—or pixel—only one of the three R, G and B signals) to an image signal which has at each pixel an R signal, a G signal and a B signal.
It is well known that cross-color and “barber's pole” artefacts can result from basic Bayer mask decoders.
Many suggestions have been made for producing more sophisticated Bayer mask decoders and reducing these artefacts. Reference is directed, for example, to GB2426881A which discloses a decoder based on non-adaptive linear filters. This decoder performs well on the G component but exhibits cross-color artefacts on the more sparsely sampled R and B components.